FANNIE MAE COMMITMENTS AND PLEDGED SECURITIES - Agency Mortgage Based Securities Pledged Securities (Detail) - Agency Mortgage Backed Securities - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investments in Agency debt securities
Fair Value	$ 106,862	$ 9,074
Amortized cost	106,963	8,981
Total gains for securities with net gains in AOCI	77	93
Total losses for securities with net losses in AOCI	(178)
Maturities - Fair Value
After one year through five years	6,356
After five years through ten years	89,671
After ten years	10,835
Total	106,862	9,074
Maturities - Amortized Cost
After one year through five years	6,362
After five years through ten years	89,819
After ten years	10,782
Total	$ 106,963	$ 8,981